Hydraulic check



`June 28, 1938. c. N. MITCHELL HYDRAULIC CHECK Filed July 15, 1935 INVENTOR.

67 V43, www 3 a5@ w4 a @5 1 4 45 .scription :set

.l yPatented June 28, 1938 I Iostrich:

sa; 'n QHYDRAULIC CHECK 34Glim's. l l:Ihisinvention-relatesas indicatedtohydraulic :checks .and 1. is directedto a check which may ;.be .used .for :numerous purposes where therelative wvementfoftwo associate-dnarts--mustbe @.911- ifit .trglled ...It is. particularly "Suited ato fthe contrel sof dom-and.-prgvdesiheffowe necessary to bring athefdoor into. its. @losedipestion as fwell'- @won- ,trolling the movement 'of the door during its"clos Aing'and opening .andthus prevent damagebeing tifo done `by the .door'moving too rapidly. A v

`l Hert`o'fore, chcks'of'tliis 'general .type .have .lacked Athe necessary "features .for universal yapplication due 'to the" abs'ence``of .convenient means loi'reversing theactiori ofthedevices, dueto the 'lack of fiheans for regulating the "forces exerted bythe operating spring', 'deitola'k o'f'controlor A Hvariations. jc'aused jby "changes in temperature and `due`t`o `no conve'r'i'ient imean'sfor adjusting the resistances 'at' various 'operating positions.

20 j ""-Th'e`principal 'objectof *thisinventionis to projvide/a hydraulic/check which is not "only-reversible -asfto-irection of rotation','but lone -wliich Lhasfrheans -for gradually varying lthe l"tension fin the VA'or'ierating spring. Another 'object 'is 5to v fpro- ;25 "videache'ck with convenient yadjustments-for"a lvariety of operating conditions. Another Lo'lsje'ot isi-to provide fa' compact andiconveriienttmeansof itemperature' control. -A further "object zis "toiproniideia means :of fpreventing'fleaks. A1s`til-lvIurther o'obje'ctlis to provide ameanswhereby the :roper- Iating spring may be secured a'gainstfllocalized .strainsizwhich result'in breakage. .Anotherobj'ect isllto provide 1an ample reservoir fof .working multi. An additional object is to provide a.'system:.idf

. u g5 .inalves .swlhich operate with-negligible resistance.

:Another .object is to provide :a unit which .can

be Aimade v.fromr 'inexpensiveparts and which 'han 'abe assembled Tat lowcost. To the accomplishl fment of 'thefforegoing and related -endsfsaidein'- 40 mention, athen,- consistsv of lthe .means illustrated `in the .accompanying drawing, described .in the following 4specification `.and :more particularly -1; 3 inie dout.in.theappended claims. v y -1 The .annexed drawing vvand ythe following rdeforth in detail ...certain .mechanism embodying `the invention, such disclosed means v.constituting.,however.. butone l.of vvariousmechan- .ical ormsin whichtheprincipleof .theinvention maybe used. l g i .In the saidfannexeddrawing fFig..-1.isa vertical l.section ...taken online-I-I of Flgv.-2. .Eig/21s -a section .online 42--2of Fig. 1. Fig. 3i\is.asection ysu stantiallyon .line3-'3 of Fig. .v2 .showing ythe springharrel I9 `partly ih .sectionand partly `in v melevation. .4 .is a --sectionmn.lined-4591 v -isra partial :section ons'line'1-1 of Fig. .1 showing" the pistonrandvalve 'structure only. Fig. 8 is a xf5 =fpartial=sectionron"line j8-8-:of Fig. 1 and constitutes -aplan view tof I thepiston only.

`In e.the :embodiment illustrated, the housing `Ill -is iprdvided `with :a :bracket rIfsI 'weldedzthereto and serving as a :means 'of attaching the check vto `10 "the door nor-other 'object with which it is used. The itopiof rthe housing .ris provided with a cover \.I2 which has ,an annulargroove' I3 serving asa reservoir. The housing fhas an outwardly exrtendin'grfiange "I I fwliiohtengages-the .inwardly ex- 115 fizending ,iflange 1:5 of 'tha-flange ring I6. The .-iltmge.f1-ing`E I6 eis :provided with :internal threads fengaging f threads on Acover `I.-2 for the tpurpose of zholdingygthiscover-fin :assembled relation with the shousingf1 .The .-upper face-of ange 4I4 is re- .-120 .fcessedjas .at-IIT to provide space Lfor angelastic gasket Adjacent ther-recess is .the edge I8 .profvvided .itorlimitwthmposition :ofthe .cover I2 .and which is machined to provide a denite depth for fthegjfhousingrfI a :25 Botatinmwithin the ghousing is --spring "barrel 4.I.; ggigrecess machined-'inL-.coverI-Z serves as the :Amper hearing-forthis-.spring -barrel and the port ning Zgisyeons ucted itc -provide .the lower bear- :ingr The spring :barrel isprovided with an ex- .Q0 Itensio l2fI of ireduo'ed .diameter which serves asV -.v-av.sha; f`tfffo the attachment of operating lever ';-2;2. ilhisaextensionghas a -conical .portion proy Nided @with :hardened flutes :.23 `which engage the ,-boretof Xilever 22. :lever fis yheld in place by'35 Aboretinto fwhich fis ainsented the rivet `-25 held in iplacef .spring 2.5. This rrivet, `which may lhave va :seatycf .soft material, serves as -a vent fvalvertofrelieve the lpressure which may 4develop 440 avithinthefcheck and-which wouldv otherwise yoauseileaksaround the .shaft packing, 2:1. This i.peeking..surJi'ournds .the shaft extension 2| and Z.engages asheveled recess provided in .cover I2. It netai-nedby-.cupfvu which lis -held in position .545 -.-.byc sp1ing .member-29. This `spring .is .formed at (3u to .engage .arecess in .lever `22 `and in the position hpwnegerts gpressure on cup .28.

. .In.theannularrfspiacesurrounding spring vbarrel n.lgs.a1-'eab1itnient.g3g-I and Wing` .piston `32 each rof. 50

whichgextendsizbetween cover -fl 2 44andvport ring 20.

..iUhe. -.=butrnent .fis l.provided lwith va longitudinal groov f33jengaging projections'or keys 34 and l.36gsite;iriped :intheavallef the housing I0. The theyrextendspartly U`into .a .slotjprovided in cover 55 i2 to hold the cover in correct angular position and key engages a slot in port ring 20, likewise to maintain correct angular relation of parts. The abutment 3l is provided with an upper passage 36 intersecting transverse port 31 and connected by passage 38 with the reservoir I 3. Likewise there is a lower passage 39 intersecting transverse port 4) and connected with the annular space @I under port ring 20 by a passage through the port ring. A pair oflleaf springs 42 and 13 secured to the abutment by rivet 44 `,serve as valves for the passage of liquid from reservoir F3 and annular space I to the working com-y partments, but automatically seal the connecting passages against a reverse flow.

The piston 32 is provided. with `inwardly.ex-lA tending keys 45 engaging slots in the wall'of spring barrel E9, this engagements'ervingfas afpositive means of rotating the piston when the spring` variations occur in this wall-or inthe spring bar-.

rel. The slots in the spring barrel are somewhat longer than the keys l5 tol permit thepiston to be centralized in the spacci between cover I2 and port ring 20 regardless of minor variations in the axial position of. the spring barrel. The central outer part of `the piston is flattened as at 46 to limit the contact with'thewall of the housing to the outer edges and thus prevent a tendency to cause a wedging action between the piston and the housing. f

Within the piston 32 is valve 41 controlling the flow through ports t8.l This valve has a reduced stem 9 surrounded bythe coiled thermostatic element 59 which has its one endengagingvalve t1 and its other end anchored in adjustable plug 5I. This plug is provided with-fine axial,- lflutes engaging' correspondingv flutes in" the end of the piston 32 and which permit of angular adjustment for the initial setting of the thermostatic valve. -f

The lower face of cover I2 sprOVi'ded-wlth an annular groove containing the severed ringmember 52. This ring member'is held inthe groove by pins as indicated at 53 and is rotated by means of the small spur gear 54" attached to shaft 55 and engaging fine gear teeth die cast in"ring 52. This ring is made in the form offan inverted channel through a part of its'ci'rcumference, these channel shaped spaces serving as adjustable relief passages between `the working compartments. The relief is provided bythe piston 32 passing over the edges of the ends of the channel sections as at .lilir in Fig. 5 thus permitting a quick movement of the piston bythe relief of `the-hydraulic pressure. The groove containing ring 52 is discontinuous at the abutment as shownat51and the ring is provided with an openingfsomewhat wider than this to permit of limited `angular movement for the adjustment above referred to.

Adjacent the abutment at bothgsides are yports 58 and 59 connected by passage' 6l). Thisy latter passage is controlled by valveBI having packing 52 and gland 63 to prevent leakage,the v`a1ve6l being a primary means'of adjustment.v The 'arm 64 serves as a means of adjusting this valve and thus regulates the flow of vliquid from one Working compartment to Athe other f through the en'- tire range of travel of 'the piston; --Supplementing the primary control as providedv by valve 6I is valve 65 engaging the lpassage A66 provided in port ring 29 and comprising a secondary Imeans of regulation. This passage 66 is formed by inserting a thin walled tube of suitable diameter and form in the die when the port ring is cast. As a further means of regulation, the ports 61 and 68 extending through the port ring into annular space 4I are provided and form a limited range of free movement for the piston.

It will be evident that, as the piston 32 is moved in a, clockwise direction by spring actuated barrel I9, reference being had to Fig. 2, the liquid contained in the portion 59 of the annular space around the spring barrel will have three passages for escape. During the rst few degrees of move- Y mentnmost of the ow will take place through port 68, annular space 4I and then through port 61intov space `lil. Some of this liquid will move l through passage 39 and port 40 into compartment 10. The ports El and 68 being relatively large there will be a very little hydraulic resistance during this limited movement. A continua.- tion of the movement of the piston 32 closes port 68 and causes flow to occur through passage 66 past valve 65. This flow continues until the plston has moved about 90 at which time the entrance to passage 66 is covered by the piston.

`As the piston moves farther, the only source vof escapeof liquid is through ports 58, 59 and BI] and past valve 6|. The speed of the door or other object to which this instrument is attached, will thus be reduced by steps, the speed being dependent on the size of the ports and the .ad-

justments of the valves. As the piston continues to move farthur under the adjustment provided by valve 6I, it will approach abutment 3l, but before reaching a position adjacent this abutment and which is theposition it occupies when the door is fully closed, the piston will pass the edge 56 of ring 52, Fig. 5, and suddenly release the pressure in space 69 by permitting now past the `upper end of the piston and through the channel shaped end of ring 52 into space 10 which now has become much larger due to the movement of the piston. The angular position `of the piston at the time of this release is determined by the position of ring 52 which is adjusted by means of gear 54 as already explained.

To provideadditional now of liquid from space |59Y to space 19 at the time of release the spring barrel I9 is cut away as at 69 and 10 providing yrotation of the spring barrel I9 under the action of vspringl must be reversed. This is accom- 'plished in a manner similar to that shown in my APatent No. 1,836,383. In the device shown on the annexed drawing, the spring 1I, which is of helical form, has its upper end secured to anchor 12 and its lower `end secured to anchor 13, the cups 12 and 13 serving as means for centering the spring on the anchors. This centering of the -spring from the outside of the coils prevents contact with the hub of the anchor which would resultin localized bending of the coil at the point v*of contact and eventual fracture of the coil at `that point.

These cups, further prevent frictional contact ofthe spring with the spring barrel which would detract from its free movement, Vthe outer diameter of the cups being somewhat qu gshaftf1-4. The anchor .Washerlhasllugs alsoenanuncie "bottom of the housing 'IIl'atits lowerr end. `Washuerf15"having.1ugs engagingrkeyways serves as 7aseat for the-nut 411. The'bottom of the housing fIlII is clamped between :washer 15 and anchor washer 18 which bearsfagainstthe shoulder von .gaging rkeyways 16 -and is providedwithsharp .hard'ened flutes whichserveas a means ofpositive engagement'with the softsteel of the hous'- Sing-to prevent rotationofgfshaft 14.` `Washer 15 khasa notch Y1.i"whichis"erves as a means ofen- .gagement for a toolto hold shaft 14 from rotating whiletightening 'nut "11. l'A'V gasket 19 is linserted betweenv thewasher J5 andthe housingv I0 to-pre-v avent Ileaks .and to furnishadditional holding lfriction... N n.

:The .upper spring anchor 12 lis provided with `anexternal lug. 80 whichengages lug8I provided An fthejnside of thegspring barreLand with an `innerwlug 82V engaging anchor pin'83 securely .driven;into shaftzll." yhelower spring anchor ;1.3.is.centeredjin tension `block '84 andfsecurely fheld from rotation relative thereto by `adjusting screw 85. This tension block has turning clear` Lance inhousing I 8. kThe upperr and lower external corners `of 'th'e tension block are: cut away as at r8.6 and;81. ythroughthe greatervpart of their cir- V ,tcumferences leaving a double lug88. The lower part pfthis'lug 88 .engages lug 89 on :the anchor vwasherpilll andthe upper part of the lug engages ,.lug;,9 on .the spring barrel I9-, The relative positions of these various lugs are .shown .most clearly vintli'igs 3 and 4. Fromthes'e guresit will be evident that when the vspringbarrel |9is rotated tinalockwise direction,v the rlug 8| Vof the spring vbarrel engaging lug80 ofthe spring anchor 12 will rotate it 4on shaft 14 causing the inner .lug .18,2

tomove r.away from .pin=83. lDuring rthis ymovermentthe spring 1I is woundup from its upper endand the lug ,90 moves away from lug-88,V the tension block 84beingheldfrom' turning by'lug .189 on anchor washer 418whichis Vsecurely-clamped einl Aposition bythe nut A'11 on the end of1shaft1i4as '.'above explained.

'iWhen the spring `barrel f|9 rotates inwan anti- .clockwise direction it .will be-evident that lugA 8| twill .moveaway from-'lug of theA spring'anch'or 12:,andxlug 82. willengage pin 483 rand thus .prevent theupper end of the Aspring and its anchor from 'rotating:relative shaft 14. The lug r9|! of the spring barrelnow engages the lug 88 of the ten- ;fsion `block 84 rotating .this block, and the lower 'spring anchor securedtheretdon shaft 14 thus winding up the spring 1| .from .its lower'end ina direction opposite `to the wind-up .at the other rend. 1

` .In order tosecuresuncient range of yangular f n movement of the springbarrel, themovementbf 'tes 4piston .32 :must begin in proximity with one side A.of :ftheiabutment 3| forerotation'in one direction-and in proximity with the other side of the abutment for rotation-in 'the `opposite direction. Tc attain .this condition, nut 11 is loosened andithe fspring barrel I9.,.carryingjthe spring, 'thevspring anchors, ,shaft and all related parts including the piston, iis rotated until thegpiston `32 contactsfwith I.the .abutment 3|. In thisposition vnut A17|` is securely tightened. The spring barrel canthenzbe rotated uin onedirection windingupspring J1.;I `from one rmnd.. 4vIl? th'efnut 111s tightened with thefpiston adjaeentthesother :sidetoffthe l abutment-'fas an the #springanchorl 13 .is z-p-rovidedrswith la -worm wheel structure hat 9| "engaging .the ladjusting Worm/or; screw85 :which has a bearing' at one endv in .tension :block 84and atthe other .end irr screw plug '92::carriedlin fthe ,tension block.`. As shown infEig'. ithe'irecess inthe tension lblock for the reception'of theadjusting worm islOcatedwithin y 111gf.88.- iIns order I:to vm'ak'e this adjusting :worm accessible :whenth'exinstrument is adjusted,A for either fclockwise for 'anti-'clockwise rotation, two openingsiare `provided' as: at '93 and 94,"one'1being for .adjustmentlwhen the check operates'v vinf-a clockwiseldirec'tion-v andthe other when it operates :in an fanti-"clockwise"rdirection. The bandi ,95 is shrunk or welded to the outside ofthe housing `Ill toiprovide 'stock for `the threadsbfflplugs 96 inserted .at 93-fand '94.* 1It .will be evidentthat, whena s`crew.:rdriveror vsuitable wrnchfis inserted finfone ,of these :openings and the adjusting :Worm turned,.the rlower yspring anchor 13 willbe :rotated fand the: ,tensionrofz' thev spring11| will be ,changed without aiectingthe position of the ,ten- -.sion-b1ock:84. i y f 1 y y y11n` order to preventl pressuresfrom building lup withinethe `instrumentvat points-Where leakage ywith they spacedirectlybelowyent valve`25.' This valve ibeing'held to itsseat by. a very light spring A ipermits the escape of gases 'under-very light pressures. Transverse; passage "91 in :association with passage 98 connects =the circumferential pas'- sage .99 adjacent gasket. |1fand :circumferential ,passage ,|00 .Withfthe reservoir. f The fhole I'IlI leading into the spring barrel Isis joined byznotch |02-, Fig. 4. andgroove |83 with the space in shaft .extension 2| adjacent valver25, thus bringing both .circumferential 'passages 99 .and I 00 as well as ithe reservoir I3 into communicationgwith a space substantially at atmospheric pressure. Pressures -:of any, appreciable magnitude are thus prevented l,from developingadjacent.gasket I1 or adjacent packing 21. Theinstrument'maybe iilled by removing the plugin the top of "passage 98 or by -removinglever screw .24. A hole :|04 is provided inthe .spring barrel I9 .connecting the annular .space 4I .with the interior vof the spring barrel.

`This passage Vpermits; of the circulation of the 'i AAttention is-directed to the-simplicity `of the `'various yparts entering into the construction of ithisrdevice which permits ofinexpensivefmethods y inexpensively yof sheet metal withno interior .'machinin'g or lgrinding required. The -cover @I2 xisfofsuch lform as to oe-machined fullyVexcept for .small .-.drilled holes, in one vvset-up and` froma of manufacture. The housing I0 is made-very 70 l every1 simple feasting. The spring barrel lI8` `with its extension 2l is made very economicallyby providing a top member made on an ordinary screw machine and then welding this top -to a piece of tubing of suitable size after which Ythe assembly thus formed is passed through a centerless grinder to insure a correct outeridiameter. Other parts such as piston 32, abutment I, spring anchor 12, port ring 20 and tension block 84 are produced at very low cost as die castings requiring very little if any machining, the construction of the entire unit being such as to permit of considerable variation in the dimensions Aof practically all parts. 1 l

Other modes of applying the principle of my invention may be employed instead of the one explained,' change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims orthe equivalent of such stated means be employed.

I therefore point out and distinctly claim as my invention:

1i. In a hydraulic check, a casing having an abutment therein, a spring barrel within said casing, a channel surrounding the spring barrel, a vane in the channel being secured to said spring barrel, means for oscillating said spring barrel, a spring for returning said spring barrel to its original position, meansk arranged within said casing and moveable to diier-ent positions to connect said spring barrel with either end of said spring, and means for regulating the tension of said spring.

2. A hydraulic check of the class described comprising a casing having an abutment, a spring barrel within said casing and dividing the same linto a pair of compartments and having a portion projecting through said casing, the abut'- ment and a piston being in one of the compartments, a lever non-rotatably secured to said pro- ;4'fjecting portion, a shaft arranged within said spring barrel, a spring associated with said' shaft, spring anchors supported by said shaft and connected to the opposite ends of said spring, manually operable meanscarried by said shaft and adapted to be selectively positioned to con-v nect said spring barrel with either one of said spring anchors and to hold the other spring anchor against turning whereby said spring may be wound up from either end selectively and a means for adjusting the position of one of said spring anchors relative said shaft.

3. In a hydraulic check, a casing having an abutment and a piston therein forming a pair of working compartments, a spring actuated member serving as a rotatable shaft in said casing, the piston being operated by` said spring actuated member, a cover for said casing, said cover including a reservoir, and a leaf spring .check valve adapted to deliver liquid from said reservoir to one of said working compartments.

4. In a hydraulic check, a casing having an abutment and a piston therein forming a pair of working compartments, a spring actuated member serving as a rotatable shaft in said casing, the piston being operated by said spring actuated member, a cover for said casing, said cover including a reservoir, a check valve comprising a flexible element covering a passage from said reservoir and a vent valve` adapted to relieve pressures within said reservoir.

` f5. In a hydraulic check, a casing, a hollow. cylinder serving as a shaft, a piston in said casing and operable by said cylinder, an abutment, said -piston and said abutment in association with the casing and the hollow cylinder defining two Working `compartmentsa cover for said casing, a primary means cf adjustment associated with said cover andadapted to regulatethe flow of liquid betweenv said'. working compartments and a secondary means of adjustment independent of said primary means of adjustment, the now through the saidY secondary adjustment dependentupo'n the, position of the aforesaid piston. g 6. In a lhydraulic, check, a casing, a rotatable cylinder serving as' a shaft, a piston in said casing and operablefrom said rotatable cylinder, an abutment, said abutment in association With said shaft and said piston forming a partition between tWo Working compartments, a valve in said partition, saidvalve having an elongated stem,l a part of said valve cut away to provide a variable passage, a coiled thermostatic element surrounding the stern of said valve, and a means for` adjusting the initial position of said valve.

'7. In aghydraulic check, a casing, a`rotatable cylinder serving as a shaft being journaled in said casing, a piston operable from said rotatable cylinder, an'abutment, said piston and said abutmentin association with the `cylinder and casing defining a pair of working compartments, a passage between said; working compartments, said passage ybeing controlled by the aforesaid piston, and means'for adjusting the position of said passage. l

8. In a vhydraulic check, al casing, a cover for said casing, a hollow cylinder serving as `a shaft being journaled'therein, apiston operable from said hollow cylinder, a reservoir, a vent valve adap-ted to relieve the pressure in said reservoir, an annular vent passage in said cover and a passage connecting said annular vent passage and said reservoir.

9. In a hydraulic `checlc'a casing, a tubular member serving as a shaft being journaled in said casing, a piston in said casing and operable from said tubular member, an orifice in a wall of said casing, said orifice constituting a fixed adjustment for controlling the movement of the piston through a portion of its travel, and a valve adjustable to regulate the movement of they piston through other parts of its travel.

10. In a hydraulic-check, a casing, a member serving as a rotatable shaft being journaled in said casing, a piston in said casing and operable by said member, an orice in the wall of the casing, said orice constituting a fixed vadjustment for controlling the movement of said piston through a portion of its travel, and a second orifice having a manual adjustment, the said second orifice being closed by the ymovement of said piston.

.11. In a hydraulic check, a casing, a rotatable member serving as a shaft being journaled in said casing, a piston in said casing and operable from said rotatable member, a vent passage constituting an adjustment for the initial movement of said piston, a. second passsage constituting an` adjustment for a further movement of said piston and a valve adapted to regulate the movement of the piston beyond the control of the said second passage.

12. In a hydraulic check, a casing, a rotatable member serving as a shaft being journaled therein, a-piston in said casing and operable from said shaft, a vent passage `constituting an adjustment for the initial movement of the said piston, a second passage constituting an adjustment for a `further movement of said piston, a valve adapted to regulate the movement of said piston beyond the control ofthe said second passage Aand arancia means for releasing,fpressurencontrolledz. by. the

" said: valve upon aiccntinuedimavementfotithefsad piston. ryel'SJIn ai. hydraulicchck:jatcasing, a rotatable member serving:A as am shaftbeing'fj'ournaledthere@ in; `a.' pistonfinrsaid fcasingand ioperable'irom i said rotatablev membergafvent/ passage;constitutingfan adjustment for.. theA initialimovementtofi the-,said

` piston, a second apassage .constitutingaannadjusti ment: forV a further lrnovement, off-said; piston-,fg a .valve adapted to regulate, the: movement -of:;said .pistombeyond the control :,.ofx-the; said :second ypassage*y and anadjustableameans: forrel-easing pressurecontrolled bythe sa-idfvalvefz-- passages?A from the'r` reservoir.

14-a In'. a hydraulic checaaccasingynaving'a pair f of working icomparftments, a rotatable meme ben serving Yas af shaft being. insaid casing; ai piss .ton operated b'v said rotatable*` memben; ai .cover for saidrcasing, a reservoirl associated' with-fisai'd casing; la check; valve'c'omprising ai flexible`1 ele# ment:covering:apassageffroms d reservoir; said valve controlling uthe flow of d'zafthrough ,-15. Ina hy`dr ulic'checlr;- 'casingfhaving'fa'pair of f working. compartments; :ia rotatable" member serving i as a'`- shaft -beingf inrfsaidicasing;l a'- piston operated by. said; rotatable-:member v'ai spring adapted to. .returna thefseiid shafftztoi its f initial? position; anchorsf for saidfz'springgeands-means; for centering the. coilsioft said` spring withzrespeet to s'aidnanchors. J- :.:.Y.;j; f r'; -g-

y16.cIni ai -hydraulicficheckg a leasing;` ai rotatable memberl serving as a: shaftY `beings.'journaled'in Y said casing;axpiston"l operable. bwsaid shaitgta ber 4provided with key means of interconnectiom. said key means having clearance' adapted to permit of limited oscillatory movement of said piston relative tc the key means in said rotatable member. v

18. In a hydraulic check, a casing, a rotatable member' serving as a shaft being journaled in lsaid casing, a piston operable by said rotatable member, an abutment associated with said casing and said rotatable member, said abutment and said casing being provided withfinterengaging f' means, said means having clearance and adapted to permit a limited movement of said abutment relative to the casing.

19. In a hydraulic check, a casing, an arm actuated member serving as 'a shaft within the casing, said casing and said arm actuated member dening an annular channel, a wing piston in said channel, the wing piston being secured to the arm member, means for oscillatingsaid member, a return spring having connection within said member, and adjusting means within the casing for changing the tension of said spring.

i 20. In a hydraulic check, a vcasing having an abutment keyed therein, a hollow member serving as a shaft in said casing, an annular channel surrounding said hollow member, a piston being operated by said hollow member, the said piston and said abutment dividing the annular channel into two working chambers, a spring adapted to returnv thehollcwcmemben tol its initial position, -ahchbrsi :for said: :spr-ing; .-zand. :i vscrew.: actuated meansifor fadjusting the,T relative positions-:ofi said anchorsmzla- 1' g' :5a. l 221.1;1n;a a1 hydrauli checkyha asing! having an annular channel therein, an abutment anda'wing piston dividing i theif channelz into',v`v two. working compartments', a' springactuatedmember serving asiaishaftwin said casing,l thefpistonbeing; op,- eratedwbyf said.. spring actuated'fmernber, aY cover tonsaid` casing; said cover co1-operating` ,withthe casing to de nesanfannular reservoir; and a check valveff-adaptedzeto eliver liquidatoj a working cornparf/mentk l ,.1 l. .l 1s: 22. l.In a. hydraulic check, a casing -having `an annular channel, an abutment and. awing'piston dividing the `fchannel rinto `twoeworlcingY chambers, ai spring.'v actuated. member: serving@ as a shaft, saidnpistonfbeingzsecured to'fsaidz'memb'er; aicover for' saifdf casing; .said cover having "a :channel cut in amperipheral'-part' thereof said--channel'fibeing closed'sbylaparttofithe casingftoxformva reservoir;

a= :checkvfval've controlling a flowof@ liquid f from the* -rr-.eservoin and a= :vent fvalvez for f relieving pressurefwithinfltne."reservoira i.

23;` i In a# fhydraulicl check, a casingzshaving a pairof.working'c'ompartments, a rotatablemem: benserving-fasi-a shattxbeingin said casi-ng, a ypiston openated by; said ,L rotatable member;y 1an annular Wall :serving aseeaiclosurey for: an endY of' the casing",

itl

ai substantially-arcuate. member :being y carriedfiby said ;wal1;v and `means for adjustingiheisaidi arcu-f.

atemember; .2,- l 24;.Infafhydra io,check,';a.casing h aof* workincvcompartments, azsrotatable sen/ingresa s piston .operate piston having ,Ea ke .extendinaintc :a member, and the key being smaller than the recess to permita limited movement of the piston relative to the rotatable member.

25. In a hydraulic check, Aa casing having an annular chamber, a piston and an abutment in said annular chamber, a member serving as a .ninfa :Wallf .the rota-table ed to return the member to an initial position, n

an anchor for the spring, said anchor having engagement with `a tension member, means for y 4moving 'said spring seat relative to the tension lmember, and means for selectively locating the tension memberV to reverse the action of the f spring. f

26. In a hydraulic check, a casing having an annular chamber, said annular y chamber having a bottom wall and a top wall, a piston and an abutment dividing the annular chamber into two compartments, the bottom wall comprisingan annular passage joining the two compartments,

the passage. 1

27.v In a hydraulic viding the annular chamber into a pair of compartments, a cover for the casing having a reserand means for regulating a flow of fluid through check, a casing having anv annular chamber, a piston and an abutment di-l l voir, a tubular member serving as a shaft, `a

bearing for said tubular member in said cover,

. and an annular passage within said cover acl-v annular chamber, said annular chamber having l a top wall and a bottom wall, a piston and an abutment dividing the annular chamber into two 45* shaft operating said piston, a spring being Vadapt-` compartments, a tubular member serving as a shaft, said tubular member having a bearing in the bottom wall, an annular passage adjacent to said bearing, and an opening connecting the annular passage with an interior part of the tubular member.

29. In a hydraulic check, a substantially cylindrical casing having an annular chamber, a piston and an abutment dividing the annular chamber into a pair of compartments, a member in said casing serving as a shaft, the said piston having an axially extending passage, a substantially cylindrical valve in said passage, a thermostatic element engaging said valve, and means for selectively locating said thermostatic element in the passage.

30. In a hydraulic check, a casing, an arm actuated member serving as a shaft within the casing, said casing and said arm actuated member defining an annular channel, a member in said channel dividing the channel into a pair of working compartments, means holding said member relative to a wall of the channel, said holding means having clearance `to"permit a pressure of fluid to move said memberfinto sealing contact with said wall, a passage through said member, a substantially cylindrical valve in said passage, and a temperature responsive element engaging said valve, said element extending substantially axially through said member.

31. In a hydraulic check, a casing, an arm actuated member serving as a shaft withinfthe casing, said casing and said arm actuatedmember dening an annular channel, amernber in said channel dividing the channel into two working compartments, means holding said member relative to a wall of the channel, and a passage through said member, a strip of metal being attached to a Wall of the member at a substantial distance from the passage, and the said strip being bent by a flow of fluid to open and close said passage.

32. In a hydraulic check, a casing, an arm actuated member serving as a shaft Within the casing, said casing and said arm actuated member dening an annular channel, an abutment in said channel `dividing the channel into two Working compartments, and means holding said` abutment relative to a wall of the casing, the member serving as a shaft having a part of its surface cut away to provide a passage between the working chambers when the said part of the surface thus cut away passes the abutment.

33. In a hydraulic check, a casing, a hollow arm actuated member serving as a shaft within the casing, said casing and said arm actuated member defining an annular channel, an abutment in the channel, the hollow arm actuated member containing working fluid, a poppet type vent valve in said arm actuated member, said vent valve comprising a head and a split stem, the head of said last named member engaging a seat in the arm 'actuated member, the split stem ofthe valve being spread to engage a surrounding spring, and the spring being tensioned to hold the said head of the valve on a seat.

34. In a hydraulic check, a casing, an arm actuated member serving as a shaft within the casing, said casing and said arm actuated member defining an annular channel, anv abutment in the channel dividing the channel into two working compartments, a cover for the casing, a passage in the cover, the said passage connecting the working compartments, a substantially ,cylindrical valve in. the passage, and -an arm for rotating said valve, said arm being adaptable to be bent to la desired position.

COURTNEY N. MITCHELL. 

